title: Axon guidance: asymmetric signaling orients polarized outgrowth.
abstract: A network of connections is established as neural circuits form between neurons. To make these connections, neurons initiate asymmetric axon outgrowth in response to extracellular guidance cues. Within the specialized growth cones of migrating axons, F-actin and microtubules asymmetrically accumulate where an axon projects forward. Although many guidance cues, receptors and intracellular signaling components that are required for axon guidance have been identified, the means by which the asymmetry is established and maintained is unclear. Here, we discuss recent studies in invertebrate and vertebrate organisms that define a signaling module comprising UNC-6 (the Caenorhabditis elegans ortholog of netrin), UNC-40 (the C. elegans ortholog of DCC), PI3K, Rac and MIG-10 (the C. elegans ortholog of lamellipodin) and we consider how this module could establish polarized outgrowth in response to guidance cues.
authors.affiliation: Department of Pathology, University of Medicine and Dentistry of New Jersey-Robert Wood Johnson Medical School, Piscataway, NJ 08854-5635, USA. QuinnCC@umdnj.edu
authors.forename: Christopher C
authors.initials: CC
authors.lastname: Quinn
authors.forename: William G
authors.initials: WG
authors.lastname: Wadsworth
mesh_terms: D000818:Animals; D001369:Axons / Q000378:metabolism*; D017173:Caenorhabditis elegans / Q000378:metabolism / Q000502:physiology; D029742:Caenorhabditis elegans Proteins / Q000378:metabolism*; D002465:Cell Movement / Q000502:physiology*; D003599:Cytoskeleton / Q000378:metabolism; D020439:Growth Cones / Q000378:metabolism; D015398:Signal Transduction / Q000502:physiology
chemical_list: D029742:Caenorhabditis elegans Proteins